Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.
Grok 4.1 Fast is clearly ahead on the aggregate, 76 to 33. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Grok 4.1 Fast's sharpest advantage is in multimodal & grounded, where it averages 87.4 against 32.4. The single biggest benchmark swing on the page is HumanEval, 86 to 17.
LFM2.5-1.2B-Thinking is the reasoning model in the pair, while Grok 4.1 Fast is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Grok 4.1 Fast gives you the larger context window at 1M, compared with 32K for LFM2.5-1.2B-Thinking.
Pick Grok 4.1 Fast if you want the stronger benchmark profile. LFM2.5-1.2B-Thinking only becomes the better choice if you want the stronger reasoning-first profile.
Grok 4.1 Fast
71
LFM2.5-1.2B-Thinking
34.1
Grok 4.1 Fast
59.5
LFM2.5-1.2B-Thinking
8.2
Grok 4.1 Fast
87.4
LFM2.5-1.2B-Thinking
32.4
Grok 4.1 Fast
88.3
LFM2.5-1.2B-Thinking
38.4
Grok 4.1 Fast
69.2
LFM2.5-1.2B-Thinking
27
Grok 4.1 Fast
90
LFM2.5-1.2B-Thinking
72
Grok 4.1 Fast
84.8
LFM2.5-1.2B-Thinking
60.7
Grok 4.1 Fast
92.3
LFM2.5-1.2B-Thinking
42.3
Grok 4.1 Fast is ahead overall, 76 to 33. The biggest single separator in this matchup is HumanEval, where the scores are 86 and 17.
Grok 4.1 Fast has the edge for knowledge tasks in this comparison, averaging 69.2 versus 27. Inside this category, MMLU is the benchmark that creates the most daylight between them.
Grok 4.1 Fast has the edge for coding in this comparison, averaging 59.5 versus 8.2. Inside this category, HumanEval is the benchmark that creates the most daylight between them.
Grok 4.1 Fast has the edge for math in this comparison, averaging 92.3 versus 42.3. Inside this category, AIME 2023 is the benchmark that creates the most daylight between them.
Grok 4.1 Fast has the edge for reasoning in this comparison, averaging 88.3 versus 38.4. Inside this category, SimpleQA is the benchmark that creates the most daylight between them.
Grok 4.1 Fast has the edge for agentic tasks in this comparison, averaging 71 versus 34.1. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.
Grok 4.1 Fast has the edge for multimodal and grounded tasks in this comparison, averaging 87.4 versus 32.4. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.
Grok 4.1 Fast has the edge for instruction following in this comparison, averaging 90 versus 72. Inside this category, IFEval is the benchmark that creates the most daylight between them.
Grok 4.1 Fast has the edge for multilingual tasks in this comparison, averaging 84.8 versus 60.7. Inside this category, MGSM is the benchmark that creates the most daylight between them.
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